JP2012176353A - Substrate washing system, substrate washing method, apparatus for manufacturing display device, and method for manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the number of washing processes, and additionally to prevent the re-attachment of contaminant particles to a substrate.SOLUTION: A substrate washing system 1 includes a conveying part 2 that conveys the substrate W, and a supply nozzle 3 that supplies a washing liquid, having oxidative gas in a state of dissolved and of microbubbles in an oxide film-removable liquid, to a washing surface S of the substrate W conveyed by the conveying part 2. The supply nozzle 3 supplies the washing liquid at a flow velocity at which microbubbles reached on the washing surface S move to the periphery of the substrate W suppressing a size change.

Description

  The present invention relates to a substrate cleaning apparatus and a substrate cleaning method for cleaning a substrate with a cleaning liquid, and further to a display device manufacturing apparatus and a display device manufacturing method.

  A substrate cleaning apparatus supplies a cleaning liquid to the surface of a substrate such as a glass substrate or a semiconductor wafer in a manufacturing process of a liquid crystal display device or a semiconductor device, and cleans the substrate surface. Among the substrate cleaning apparatuses, for example, there is a substrate cleaning apparatus that supplies a cleaning liquid to the substrate surface while transporting a substrate to be cleaned.

In substrate cleaning using a cleaning solution, for example, when substrate cleaning is performed by a lift-off method, organic substance removal and oxide film formation with ozone water (O ₃ water) are performed, and then oxidation with dilute hydrofluoric acid solution (DHF solution). Film removal is performed (see, for example, Patent Document 1). As a result, contaminant particles are removed from the substrate surface.

JP 2002-131777 A

  However, the above-described substrate cleaning requires two cleaning steps, that is, a step of removing organic substances using ozone water and forming an oxide film and a step of removing oxide film using a diluted hydrofluoric acid solution. In addition, after removal of the oxide film with a dilute hydrofluoric acid solution, contaminated particles once removed may reattach to the substrate surface.

  The present invention has been made in view of the above, and an object of the present invention is to reduce the number of cleaning steps, and further to prevent the reattachment of contaminant particles to the substrate. Another object is to provide a display device manufacturing apparatus and a display device manufacturing method.

  In a substrate cleaning apparatus, a first feature according to an embodiment of the present invention is that an oxidizing gas is contained in a liquid from which an oxide film can be removed on a transfer unit that transfers a substrate, and a surface to be cleaned of the substrate transferred by the transfer unit. A supply nozzle that supplies a cleaning liquid having a dissolved state and a microbubble state, and the supply nozzle supplies the cleaning liquid at a flow rate at which the microbubbles that have reached the surface to be cleaned move to the outer edge of the substrate while suppressing size change. That is.

  A second feature according to the embodiment of the present invention is that, in the substrate cleaning apparatus, an oxidizing gas is contained in a liquid from which an oxide film can be removed on a transport unit that transports the substrate and a surface to be cleaned of the substrate transported by the transport unit. A plurality of supply nozzles for supplying a cleaning liquid having a dissolved state and a microbubble state, and the plurality of supply nozzles are arranged side by side in a direction crossing the substrate transport direction along the surface to be cleaned. In the plane parallel to the surface to be cleaned of the substrate, they are inclined in the same direction with respect to the substrate transport direction, and are inclined in the same direction with respect to the surface to be cleaned of the substrate.

  A third feature of the embodiment of the present invention is that in the substrate cleaning method, an oxidizing gas is contained in a liquid from which an oxide film can be removed on a transport unit that transports the substrate and a surface to be cleaned of the substrate transported by the transport unit. A substrate cleaning method for cleaning a substrate using a substrate cleaning apparatus including a supply nozzle that supplies a cleaning liquid in a dissolved state and in a microbubble state, and the substrate to be cleaned transported by a transport unit by the supply nozzle The cleaning liquid is supplied to the surface at a flow rate such that the microbubbles that have reached the surface to be cleaned move to the outer edge of the substrate while suppressing the size change.

  According to a fourth aspect of the present invention, in the substrate cleaning method, an oxidizing gas in a liquid from which an oxide film can be removed is provided on a transport unit that transports the substrate and a surface to be cleaned of the substrate transported by the transport unit. A substrate cleaning method for cleaning a substrate using a substrate cleaning apparatus comprising a plurality of supply nozzles each supplying a cleaning liquid having a dissolved state and a microbubble state, wherein the plurality of supply nozzles are surfaces to be cleaned of the substrate Are arranged side by side in a direction crossing the substrate transport direction, and are inclined in the same direction with respect to the substrate transport direction in a plane parallel to the substrate surface to be cleaned. In other words, the cleaning liquid is supplied to the surface to be cleaned of the substrate transported by the transport unit by a plurality of supply nozzles.

  A fifth feature according to the embodiment of the present invention is a display device manufacturing apparatus including a substrate cleaning device for cleaning a substrate used in the display device in the display device manufacturing apparatus. A substrate cleaning apparatus according to the first or second feature of the present invention.

  A sixth feature according to an embodiment of the present invention is a display device manufacturing method including a substrate cleaning process for cleaning a substrate used in the display device, wherein the substrate cleaning process includes the above-described method. The substrate is cleaned using the substrate cleaning method according to the third or fourth feature.

  According to the present invention, the number of cleaning steps can be reduced, and contamination particles can be prevented from reattaching to the substrate.

1 is a diagram illustrating a schematic configuration of a substrate cleaning apparatus according to a first embodiment of the present invention. FIG. 3 is a first explanatory diagram for explaining a cleaning process of substrate cleaning performed by the substrate cleaning apparatus shown in FIG. 1. It is the 2nd explanatory view for explaining the above-mentioned washing process. It is the 3rd explanatory view for explaining the above-mentioned washing process. It is a top view showing a plurality of supply nozzles with which a substrate cleaning device concerning a 2nd embodiment of the present invention is provided. It is a side view which shows the supply nozzle shown in FIG. It is a 1st explanatory view for explaining a manufacturing process of an amorphous silicon thin-film transistor concerning a 3rd embodiment of the present invention. It is the 2nd explanatory view for explaining the manufacturing process following the above-mentioned FIG. FIG. 9 is a third explanatory diagram for describing a manufacturing process subsequent to FIG. 8 described above. It is a 1st explanatory view for explaining a manufacturing process of a polysilicon thin film transistor concerning a 4th embodiment of the present invention. It is the 2nd explanatory view for explaining the manufacturing process following the above-mentioned FIG. FIG. 12 is a third explanatory diagram for describing a manufacturing process subsequent to FIG. 11 described above.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  The substrate cleaning apparatus 1 (see FIG. 1) according to the first embodiment of the present invention is provided as a part of a manufacturing apparatus for manufacturing a liquid crystal display which is a display device. A manufacturing apparatus (not shown) for producing a TFT circuit and an electrode pattern for driving a liquid crystal on W, and a light distribution film forming apparatus for forming a light distribution film on a substrate W on which the TFT circuit and the electrode pattern are formed (see FIG. (Not shown), a seal forming apparatus (not shown) for forming a frame-shaped seal surrounding the display area of each cell unit on the substrate W on which the alignment film is formed, and each cell unit of the substrate W on which the seal is formed A liquid crystal supply device (not shown) for dropping a liquid crystal material on the display area, a substrate bonding device (not shown) for bonding the substrate W on which the liquid crystal material is dropped and another substrate, and after bonding the substrates Seal to harden seal Has a like apparatus (not shown), also includes a substrate cleaning apparatus 1 for cleaning the required locations of the substrate transfer step between the production apparatus and equipment.

  As shown in FIG. 1, the substrate cleaning apparatus 1 according to the first embodiment supplies a cleaning liquid to a transport unit 2 that transports a substrate W and a surface S to be cleaned of the substrate W transported by the transport unit 2. The supply nozzle 3, the pressure dissolving part 4 for dissolving the gas in the cleaning liquid, the pump 5 for liquid supply, the liquid supply part 6 for supplying the cleaning liquid, the gas supply part 7 for supplying the gas, and the respective parts are controlled. And a control unit 8.

  The transport unit 2 includes a plurality of rollers 2a aligned in parallel with each other and a rotation motor 2b that is a drive source for rotating the rollers 2a. Each roller 2a is rotatably provided, and is arranged at equal intervals. The rotary motor 2 b is electrically connected to the control unit 8, and its driving is controlled by the control unit 8. The transport unit 2 rotates each roller 2a by a rotary motor 2b, and moves the rectangular substrate W placed on the roller 2a in the direction of arrow A in FIG.

  The supply nozzle 3 is provided above the transport unit 2, sprays a cleaning liquid toward the surface to be cleaned S of the substrate W moved by the transport unit 2, and supplies it onto the surface to be cleaned S. As the supply nozzle 3, for example, a one-fluid nozzle (one-fluid ejection nozzle) that ejects the cleaning liquid is used.

  The pressure dissolution unit 4 is connected to the supply nozzle 3 by a pipe 11 serving as a liquid supply flow path. The gas is dissolved in the cleaning liquid under high pressure, and the cleaning liquid in which the gas is dissolved is connected to the supply nozzle 3. Supply through. The pressure dissolving part 4 functions as a dissolving part for dissolving a gas in the cleaning liquid.

  In the pipe 11, a valve 11 a for adjusting the flow rate is provided in the vicinity of the supply nozzle 3. The valve 11 a is electrically connected to the control unit 8, and its driving is controlled by the control unit 8. The pipe 11 is provided with a flow meter 11b for measuring the flow rate. The flow meter 11 b is electrically connected to the control unit 8, and the measurement result is input to the control unit 8.

  Here, when the valve 11 a is opened, the cleaning liquid containing dissolved gas is jetted from the supply nozzle 3. At this time, the pressure of the cleaning liquid is released to atmospheric pressure, and the pressure released cleaning liquid becomes supersaturated with respect to the dissolved gas, so that a large amount of microbubbles are generated in the cleaning liquid. Accordingly, the supply nozzle 3 ejects the cleaning liquid toward the surface to be cleaned S of the moving substrate W, and supplies the cleaning liquid containing microbubbles onto the surface to be cleaned S.

  Microbubbles are microbubbles including concepts such as microbubbles (MB), micronanobubbles (MNB), and nanobubbles (NB). For example, microbubbles are bubbles having a diameter of 10 μm to several tens of μm, micronano bubbles are bubbles having a diameter of several hundred nm to 10 μm, and nanobubbles are bubbles having a diameter of several hundred nm or less.

  The pump 5 is provided on the upstream side of the pressure dissolving unit 4 in the liquid supply channel, and serves as a drive source for supplying the cleaning liquid to the supply nozzle 3. The pump 5 is electrically connected to the control unit 8, and its driving is controlled by the control unit 8.

  The liquid supply unit 6 is connected to the pressure dissolution unit 4 via the pump 5 by a pipe 12 serving as a liquid supply flow path, and supplies the liquid to the pressure dissolution unit 4. Here, as the liquid, a liquid capable of removing an oxide film, for example, a diluted hydrofluoric acid (DHF) solution is used. In addition to this, a surfactant or the like can be used.

The gas supply unit 7 is connected in the middle of the pipe 12 of the liquid supply channel by a pipe 13 serving as a gas supply channel, and supplies the gas to the cleaning liquid that passes through the pipe 12 and includes it. Here, as the gas, an oxidizing gas, for example, ozone (O ₃ ) is used.

  The pipe 13 is provided with a valve 13a for adjusting the flow rate. The valve 13 a is electrically connected to the control unit 8, and its driving is controlled by the control unit 8. The pipe 13 is provided with a flow meter 13b for measuring the flow rate. The flow meter 13 b is electrically connected to the control unit 8, and the measurement result is input to the control unit 8.

  The control unit 8 includes a microcomputer that centrally controls each unit and a storage unit that stores substrate cleaning information and various programs related to substrate cleaning. Based on the substrate cleaning information and various programs, the control unit 8 ejects the cleaning liquid toward the surface to be cleaned S of the moving substrate W by the supply nozzle 3 while transporting the substrate W by the transport unit 2. A cleaning liquid containing a large number of microbubbles on the surface S to be cleaned, more specifically, a cleaning liquid having ozone as an oxidizing gas in a dissolved state and a microbubble state in a dilute hydrofluoric acid solution that is a liquid capable of removing an oxide film. Perform substrate cleaning. The amount of microbubbles generated can be changed by adjusting the opening degree of the valve 13a by the control unit 8 and adjusting the amount of gas supplied to the cleaning liquid.

When the above-described cleaning liquid is supplied onto the surface to be cleaned S of the substrate W, as shown in FIG. 2, the organic substance F1 on the surface to be cleaned S is removed by ozone O ₃ which is a dissolved gas in the cleaning liquid, and at the same time, The surface to be cleaned S is modified by the ozone O ₃ , and an oxide film F2 is formed on the surface to be cleaned S. As a result, the contaminating particles M covered with the organic matter F1 are covered with the oxide film F2, and the contaminating particles M present on the organic matter F1 are oxidized by the ozone O ₃ to become the metal oxide Ma. Further, as shown in FIG. 3, the oxide film F2 on the surface to be cleaned S is removed by hydrogen fluoride HF in the cleaning liquid. As a result, the contamination particles M and the metal oxide Ma covered with the oxide film F2 are removed from the surface to be cleaned S. Note that ozone O ₃ reacts with the organic matter F1 and is decomposed, whereby CO ₂ , CO, and H ₂ O are generated.

  Further, as shown in FIG. 4, a plurality of negative potential microbubbles adhere to positive potential contaminant particles (for example, aluminum particles) M and surround the contaminant particles M. At this time, when the substrate W has a positive potential, a plurality of negative bubbles having a negative potential adhere to the surface S to be cleaned of the substrate W. As a result, a large number of micro bubbles surrounding the contaminated particles M repel potential with a large number of micro bubbles on the surface to be cleaned S of the substrate W, and the contaminated particles M once removed on the surface to be cleaned S of the substrate W. Reattachment is prevented. Even when the substrate W has a negative potential, the microbubbles surrounding the contaminating particles M repel the potential with the surface to be cleaned S of the substrate W. Adhesion is prevented.

  Such three phenomena (phenomenon as shown in FIGS. 2, 3, and 4) sequentially occur at various locations on the surface S to be cleaned of the substrate W. As a result, organic substance removal and oxide film formation by ozone and oxide film removal by dilute hydrofluoric acid solution are simultaneously performed, so that the number of cleaning steps can be reduced. Furthermore, since a plurality of microbubbles adhere to the contamination particles M and surround the contamination particles M, it is possible to prevent the contamination particles M once removed from reattaching to the surface to be cleaned S of the substrate W.

  Here, in order to improve the cleaning performance of cleaning the surface to be cleaned S of the substrate W with the cleaning liquid containing microbubbles, the microbubbles contained in the cleaning liquid ejected from the supply nozzle 3 are converted into the surface to be cleaned S of the substrate W. For example, it is important to reach the outer edge of the substrate W while maintaining the diameter while suppressing the size change. The microbubbles on the surface to be cleaned S may be combined with other microbubbles, or may disappear with the passage of time, so that the diameter does not reach the outer edge of the surface S to be cleaned. There is. In this case, the effect of preventing the re-deposition described above is insufficient, and the cleaning ability is reduced. In order to further improve the cleaning ability due to the above three phenomena, it is necessary to sequentially replace the cleaning liquid on the surface S to be cleaned of the substrate W.

  For example, when a cleaning device of a type that supplies a cleaning liquid to the substrate W on the stage while rotating the stage with the center of the stage as the center of rotation is mounted on the stage, a circular substrate W is placed on the substrate W. The cleaning liquid supplied to the substrate spreads toward the outer edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W. In such a case, the cleaning liquid may simply be supplied near the center of the surface S to be cleaned of the substrate W. However, when the substrate W is transported in one direction as in the first embodiment of the present invention. Therefore, it is necessary to pay attention to the spread of the cleaning liquid on the surface S to be cleaned of the substrate W.

  Therefore, in the first embodiment of the present invention, the flow rate of the cleaning liquid ejected by the supply nozzle 3 is such that the microbubbles that have reached the surface S to be cleaned of the substrate W suppress the size change, that is, the size is within an allowable range. The flow velocity is set so as to move to the outer edge of the substrate W while maintaining the allowable size. For example, the flow velocity is set to a flow velocity that moves to the outer edge of the substrate W while maintaining the diameter of the microbubbles. As a set value for realizing this flow velocity, a value determined in advance by experiment is stored in a storage unit provided in the control unit 8, and the control unit 8 opens the valve 11a to an opening degree based on the set value. . In response to this, the supply nozzle 3 ejects the cleaning liquid at the aforementioned flow rate. If the adjustment of the flow velocity by opening the valve 11a to the set value is insufficient, the controller 8 adds the opening degree of the valve 11a according to the flow rate measured by the flow meter 11b, and the pump 5 It is possible to adjust the flow rate to the set value described above by adjusting the fluid power and the like.

  When the cleaning liquid is sprayed from the supply nozzle 3 at the above-described flow rate, a large number of microbubbles in the cleaning liquid reach the surface to be cleaned S of the substrate W, and then reach the outer edge of the substrate W while maintaining the diameter. To do. As a result, a large number of microbubbles can reliably surround the contaminated particles M removed from the surface to be cleaned S, so that the once removed contaminant particles M are reattached to the surface to be cleaned S of the substrate W. This can be surely prevented. In addition, the fact that a large number of microbubbles reach the outer edge of the substrate W while maintaining the diameter leads to obtaining a flow rate capable of reliably replacing the cleaning liquid on the surface S to be cleaned. The above-mentioned three phenomena occurring at various places on the surface S can be promoted, and the cleaning ability can be improved.

  As described above, according to the first embodiment of the present invention, the cleaning liquid contains ozone, which is an oxidizing gas, in a dissolved state and a microbubble state in a diluted hydrofluoric acid solution that is a liquid from which an oxide film can be removed. The cleaning liquid is supplied to the surface S to be cleaned of the substrate W by the supply nozzle 3. As a result, organic substance removal and oxide film formation by ozone and oxide film removal by dilute hydrofluoric acid solution are simultaneously performed, so that the number of cleaning steps can be reduced. Further, the supply nozzle 3 sprays the cleaning liquid at a flow rate that moves to the outer edge of the substrate W while maintaining the diameter, for example, while the microbubbles that have reached the surface S to be cleaned of the substrate W suppress the size change. Since the cleaning liquid is supplied onto the surface to be cleaned S, the contaminated particles M removed from the surface to be cleaned S are surely surrounded by a large number of microbubbles, so the contaminated particles M once removed are cleaned of the substrate W. Reattachment to the surface S can be reliably prevented.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.

  The second embodiment of the present invention is basically the same as the first embodiment. In the second embodiment, differences from the first embodiment will be described, the same parts as those described in the first embodiment will be denoted by the same reference numerals, and the description thereof will also be omitted.

  In the substrate cleaning apparatus 1 according to the second embodiment of the present invention, a plurality of supply nozzles 3 are provided as shown in FIG. These supply nozzles 3 are arranged in a line along a surface S to be cleaned of the substrate W in a direction that intersects the transport direction of the substrate W (the direction of the arrow A in FIG. 5), for example, the direction orthogonal to the transport direction. Further, they are inclined in the same direction with respect to the transport direction of the substrate W in a plane parallel to the surface to be cleaned S of the substrate W. Furthermore, each supply nozzle 3 is inclined in the same direction with respect to the surface to be cleaned S of the substrate W, as shown in FIG. At this time, in each supply nozzle 3, the supply port for supplying the cleaning liquid is directed downstream in the transport direction.

  Here, the substrate W tends to be larger in the future, and a plurality of supply nozzles 3 are provided as described above with the increase in size. However, as described in the first embodiment, it is necessary to pay attention to the spread of the cleaning liquid on the surface to be cleaned S of the substrate W. If a plurality of supply nozzles 3 are simply provided, adjacent supply nozzles are provided. Since the cleaning liquid sprayed from 3 interferes with each other, the microbubbles that reach the surface to be cleaned S of the substrate W are difficult to reach the outer edge of the substrate W while suppressing the size change. It becomes difficult to prevent the reattachment of the contaminating particles M to the surface.

  Therefore, as described above, the supply nozzles 3 are provided in a line in a direction orthogonal to the transport direction of the substrate W (the direction of the arrow A in FIG. 5) along the surface to be cleaned S of the substrate W. In a plane parallel to the surface to be cleaned S of the substrate W, the substrate is inclined by the angle θ1 in the same direction with respect to the transport direction of the substrate W, and is further angled in the same direction with respect to the surface to be cleaned S. It is tilted by θ2. As a result, the cleaning liquids ejected from the adjacent supply nozzles 3 flow in the same direction on the surface to be cleaned S of the substrate W, and the cleaning liquids are prevented from interfering with each other. The microbubbles that reach the surface of the substrate W can easily reach the outer edge of the substrate W while suppressing the size change, and the reattachment of the contaminating particles M to the surface to be cleaned S of the substrate W can be suppressed.

  Note that the inclination angle θ1 with respect to the transport direction of the substrate W in a plane parallel to the surface to be cleaned S is such that the cleaning liquid sprayed from the adjacent supply nozzles 3 is in the transport direction of the substrate W on the surface to be cleaned S of the substrate W. In contrast, they are set so as to be inclined by the angle θ1 in the same direction. This angle θ1 is set according to the size of the supply range in which the cleaning liquid sprayed from the supply nozzle 3 directly hits the surface S to be cleaned. Since the cleaning liquid sprayed from the supply nozzle 3 spreads in a conical shape, the supply range is affected by the separation distance between the supply nozzle 3 and the substrate W, and the separation distance is also taken into consideration.

  As described above, according to the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained. In addition, the supply nozzles 3 are arranged side by side in the direction intersecting the transport direction of the substrate W along the surface to be cleaned S of the substrate W as described above, and in a plane parallel to the surface to be cleaned S of the substrate W. Are inclined in the same direction with respect to the transport direction of the substrate W, and are further inclined in the same direction with respect to the surface to be cleaned S of the substrate W. When the cleaning liquid is supplied to the surface to be cleaned S of the substrate W by these supply nozzles 3, the cleaning liquids ejected from the adjacent supply nozzles 3 flow in the same direction on the surface to be cleaned S of the substrate W, and the cleaning liquids are in contact with each other. Since interfering with each other is suppressed, the microbubbles that have reached the surface to be cleaned S of the substrate W can easily reach the outer edge of the substrate W while suppressing the change in size, and the contamination particles on the surface to be cleaned S of the substrate W M reattachment can be suppressed.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. 7 (a) to (c), FIGS. 8 (a) to (c), and FIGS. 9 (a) and 9 (b). 7 to 9 are cross-sectional views showing an example of a method of manufacturing an amorphous silicon thin film transistor (TFT) in the order of manufacturing steps. In the third embodiment of the present invention, the substrate is cleaned by the substrate cleaning apparatus 1 according to the first embodiment. An application example in which the cleaning method is applied to a method for manufacturing an amorphous silicon thin film transistor will be described.

  First, as shown in FIG. 7A, the gate electrode 112 is formed on the glass substrate 111. The gate electrode 112 is formed by depositing a low-resistance conductive material (electrode material) on the glass substrate 111 by sputtering or vapor deposition to form a conductive layer, and then forming a resist pattern film on the conductive layer. And the conductive layer is patterned by photolithography using the resist pattern film as a mask. The gate electrode 112 is patterned in an island shape, for example.

  Note that when an active matrix substrate is manufactured as a thin film transistor substrate (TFT substrate) including the TFT, the gate line and the gate electrode 112 can be simultaneously patterned by patterning the conductive layer.

  Examples of the conductive material include, but are not limited to, low resistance metals such as aluminum, titanium, tantalum, molybdenum, indium tin oxide, tin oxide, tungsten, copper, and chromium, and alloys thereof. . The gate line and the gate electrode 112 may be formed as a single layer or may have a stacked structure in which a plurality of layers made of the conductive material are combined.

  Further, either dry etching or wet etching may be used for the patterning.

Next, as shown in FIG. 7B, a gate insulating layer 113 made of silicon nitride or the like, an amorphous silicon layer 114, phosphorus or the like is formed so as to cover the gate electrode 112 by, eg, plasma CVD or sputtering. An ohmic contact layer 115 made of n ⁺ silicon doped with an n-type impurity is continuously formed in this order from the glass substrate 111 side.

  Thereafter, as shown in FIG. 7C, the amorphous silicon layer 114 and the ohmic contact layer 115 are etched.

The amorphous silicon layer 114 and the ohmic contact layer 115 are etched by, for example, chlorine gas, hydrogen chloride, sulfur hexafluoride-based gas, or the like by dry etching, or hydrofluoric acid (HF) and nitric acid (HNO ₃ ) Can also be performed by a wet etching method using an aqueous solution obtained by diluting a mixed acid with water (H ₂ O) or acetic acid (CH ₃ COOH) as an etchant.

  Further, the resist mask used for the etching is peeled and removed using a stripping solution containing an organic alkali after the etching. FIG. 7C shows a state where the resist mask is removed after patterning the amorphous silicon layer 114 and the ohmic contact layer 115 into an island shape.

  Next, as shown in FIG. 8A, a low-resistance conductive material (electrode material) is formed on the gate insulating layer 113, the amorphous silicon layer 114, and the ohmic contact layer 115 by sputtering or vapor deposition. A conductive layer 116 to be a source electrode 116a and a drain electrode 116b (see FIG. 8B) is formed, and a resist mask is formed thereover.

  Next, the conductive layer 116 in the opening provided in the resist mask is removed by etching, whereby source / drain electrode separation patterning is performed as shown in FIG. Thereby, a source electrode 116a and a drain electrode 116b made of the conductive layer 116 are formed.

  Thereafter, as shown in FIG. 8C, etching is continued to etch the ohmic contact layer 115.

  Thereafter, as shown in FIG. 9A, the amorphous silicon layer 114 is also partially etched, and a channel etch process for adjusting the thickness of the channel portion is performed.

  After the channel etch process, the resist mask is peeled and removed using a stripping solution containing organic alkali.

Since the surface of the amorphous silicon layer 114 is hydrophobized after the channel etch process, the metal, silicon, or silicon nitride, which is a conductive layer material, is formed on the surface of the amorphous silicon layer 114 after the resist mask is peeled off. In addition, since fine contaminants (corresponding to the contaminant particles M according to the first embodiment) made of resist or the like are easily adsorbed, a variety of fine contaminants are present after the resist mask is removed. It adheres, causing defects and deterioration of characteristics. In order to remove these pollutants, conventionally, a process of performing DHF (dilute hydrofluoric acid) treatment after O ₃ water treatment has been used. However, as an effect of dissolving O ₃ MNB in DHF, by the collapse of bubbles The removal effect of entering the gap between the contaminant and the amorphous silicon surface is improved.

  Therefore, as the cleaning process after removing the resist mask, the amorphous silicon layer is supplied by supplying a cleaning liquid having ozone as an oxidizing gas in a dissolved state and a microbubble state in a hydrofluoric acid solution that is a liquid from which an oxide film can be removed. By cleaning the entire substrate including the surface of 114 (corresponding to the substrate W according to the first embodiment), contaminants and the like existing on the surface of the amorphous silicon layer 114 are removed and are prevented from reattaching. Is done. Therefore, since the substrate surface is kept clean, it is possible to contribute to the reduction of the yield reduction caused by the reattachment of contaminants and the improvement of TFT characteristics.

  Thereafter, as shown in FIG. 9B, a passivation film (protective film) 117 such as silicon nitride is formed on the entire upper surface of the glass substrate 111 by plasma CVD or sputtering.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS. 10A to 10C, FIGS. 11A to 11C, and FIG. 10 to 12 are cross-sectional views showing an example of a method of manufacturing a polysilicon thin film transistor in the order of manufacturing steps. In the fourth embodiment of the present invention, the substrate cleaning method by the substrate cleaning apparatus 1 according to the first embodiment is shown. An application example applied to a method for manufacturing a polysilicon thin film transistor will be described.

  As shown in FIG. 10A, a silicon nitride film 212 having a thickness of 50 nm and a silicon oxide film 213 having a thickness of 200 nm are formed on a glass substrate 211 as a base insulating film by plasma CVD. Subsequently, an amorphous silicon film 214 is formed to a thickness of 50 nm on the silicon oxide film 213. Next, annealing is performed at a temperature of 450 ° C. in order to reduce hydrogen in the amorphous silicon film 214. The amorphous silicon film 214 is irradiated with an excimer laser to change the amorphous silicon film 214 into a polysilicon film.

  Next, a photoresist is applied on the polysilicon film, and a predetermined resist pattern is formed through selective exposure and development processes. Then, using this resist pattern as a mask, the polysilicon film is dry etched to leave the polysilicon film 215 only in a predetermined region as shown in FIG. Thereafter, the resist pattern is removed.

  Next, a cleaning liquid containing ozone, which is an oxidizing gas, in a dissolved state and a microbubble state is supplied into a hydrofluoric acid solution, which is a liquid from which the oxide film can be removed, to form a substrate including the polysilicon film 215 (first embodiment). The surface is cleaned (corresponding to the substrate W). Contaminant particles (corresponding to the contaminating particles M according to the first embodiment) on the substrate surface and foreign matter (existing in the grain boundary generated when the amorphous silicon film 214 is changed to the polysilicon film by irradiating the excimer laser) Etc.) corresponding to the contaminating particles M according to the first embodiment are also removed at the same time, and they are prevented from reattaching. Therefore, the cleanliness and smoothness of the substrate surface are ensured, and the function of the silicon oxide film in the next step can be effectively utilized.

Next, as shown in FIG. 10C, a silicon oxide film 216 having a thickness of 30 nm is formed on the entire upper surface of the glass substrate 211 by plasma CVD. Then, an Al—Nd (aluminum-neodymium: Nd content is 2 atm%) film is formed to a thickness of 300 nm on the silicon oxide film 216 by sputtering. Thereafter, a predetermined resist pattern is formed on the Al—Nd film using a photoresist, and the Al—Nd film is dry-etched using the resist pattern as a mask to form a metal pattern 217. Thereafter, the resist pattern is removed. Then, using the metal pattern 217 as a mask, P (phosphorus) is ion-implanted into the polysilicon film 215 under the conditions of an acceleration voltage of 25 kV and an implantation amount of 7 × 10 ¹⁴ cm ⁻² , and n serving as the source and drain of the n-type TFT. A type impurity region 218 is formed. Next, the entire upper surface of the glass substrate 211 is irradiated with an excimer laser, and the implanted P is electrically activated.

  Next, as shown in FIG. 11A, the metal pattern 217 is removed by wet etching.

  Next, as shown in FIG. 11B, a silicon oxide film 219 having a thickness of 90 nm is formed on the silicon oxide film 216 by plasma CVD. Then, an Al—Nd (aluminum-neodymium: Nd content rate of 2 atm%) film is formed to a thickness of 300 nm on the silicon oxide film 219 by sputtering. Thereafter, a photoresist is used to form a predetermined resist pattern on the Al—Nd film, and the Al—Nd film is dry-etched using the resist pattern as a mask to form the gate electrode 220.

  At this time, in the TFT formation region, a region to be an LDD (Lightly Doped Drain) region 221 is provided between the edge portion of the gate electrode 220 and the source-side impurity region 218 when viewed from above.

Next, P (phosphorus) is ion-implanted into the polysilicon film 215 under the conditions of an acceleration voltage of 25 kV and an implantation amount of 7 × 10 ¹⁴ cm ^{−2 using} the gate electrode 220 as a mask, and impurity regions 218 on the source and drain sides. Next, an LDD region 221 is formed. Thereafter, annealing is performed at a temperature of 400 ° C., and P (phosphorus) implanted into the LDD region 221 is electrically activated.

  Next, as shown in FIG. 11C, a silicon nitride film 222 is formed to a thickness of 350 nm on the silicon oxide film 219 and the gate electrode 220 by plasma CVD. Thereafter, annealing is performed at a temperature of 400 ° C. to electrically activate P (phosphorus) implanted in the LDD region 221 and to the interface between the channel region and the gate oxide film by hydrogen in the silicon nitride film 222. Hydrogenate certain defects and improve TFT characteristics.

  Next, a resist film having contact hole forming openings is formed on the silicon nitride film 222 using a photoresist. Then, using this resist film as a mask, the silicon nitride film 222, the silicon oxide film 219, and the silicon oxide film 216 are dry-etched to form a contact hole that leads to the impurity region 218 of the TFT, as shown in FIG.

  Subsequently, Ti is sequentially deposited to a thickness of 100 nm, Al of 20 nm, and Ti of 50 nm on the entire upper surface of the substrate 211 by sputtering, and the contact hole is filled with these metals and a metal is formed on the silicon nitride film 222. A film is formed. Thereafter, a mask pattern is formed by photolithography, and the metal film is dry-etched to form an electrode 223 electrically connected to the source and drain of the TFT as shown in FIG.

(Other embodiments)
In addition, the above-mentioned embodiment which concerns on this invention is an illustration, and the scope of the invention is not limited to them. The above-described embodiment can be variously modified. For example, some components may be deleted from all the components shown in the above-described embodiment, and further, components according to different embodiments may be appropriately combined. Also good.

  In the above-described embodiment, pressure dissolution is used as a method for generating microbubbles. However, the present invention is not limited to this. For example, a cleaning liquid containing microbubbles is generated in advance by a microbubble generating unit, and the cleaning liquid is used. You may make it inject from the supply nozzle 3, or in the inside of the supply nozzle 3 etc., it entrains gas in the swirl of a washing | cleaning liquid, produces | generates a microbubble, and injects the cleaning liquid containing the microbubble from the supply nozzle 3. You may do it.

  Further, in the above-described embodiment, the flow rate at which the cleaning liquid is sprayed is controlled so that the microbubbles that have reached the surface S to be cleaned of the substrate W move to the outer edge of the substrate W while suppressing the size change. However, instead of this, the pressure for spraying the cleaning liquid may be controlled.

  In the above-described embodiment, the one-fluid nozzle is used as the supply nozzle 3. However, the present invention is not limited to this, and a high-pressure nozzle, an ultrasonic nozzle, or a two-fluid nozzle may be used. In particular, by using a high-pressure nozzle or a two-fluid nozzle and further increasing the flow rate and jetting pressure of the cleaning liquid ejected from the nozzle, the replacement efficiency of the cleaning liquid is further improved, so that the cleaning efficiency can be improved.

  In the above-described embodiment, the surface to be cleaned S of the substrate W may be charged to either a positive potential or a negative potential. For example, the surface to be cleaned S of the substrate W is negatively charged using a charging device. You may make it charge to. In this case, as compared with the case where the surface to be cleaned S of the substrate W has a positive potential, the microbubbles having a negative potential only adhere to the contamination particles M, and the reattachment of the contamination particles M to the surface to be cleaned S of the substrate W is achieved. Can be prevented. In particular, since fine bubbles to be attached on the surface S to be cleaned of the substrate W are not necessary, the flow rate adjustment of the cleaning liquid can be facilitated by that amount.

  In the above-described embodiment, the substrate W is transported in a horizontal state. However, the present invention is not limited to this, and the substrate W may be transported while being inclined. In this case, since the flow rate of the cleaning liquid on the surface to be cleaned S of the substrate W is higher than that of the substrate W in the horizontal state, the replacement of the cleaning liquid on the surface to be cleaned S can be promoted. The cleaning liquid is supplied toward the upper end portion of the inclined substrate W.

In the above-described embodiment, ozone (O ₃ ) is taken as an example of the oxidizing gas, but an oxidizing gas containing at least one gas of O ₂ (oxygen) and O ₃ (ozone) may be used. it can. In addition, as the oxide film removable liquid, an oxide film removable liquid containing at least one liquid of DHF (dilute hydrofluoric acid), NH ₄ F (ammonium fluoride) and H ₂ O ₂ (hydrogen peroxide) is used. Can be used.

  Depending on the application, for example, as the substrate W, an insulating substrate or a single crystal Si substrate for forming a thin film transistor can be used. In this case, it is possible to use a substrate that exhibits hydrophobicity by treatment with a liquid from which an oxide film can be removed, or a substrate that exhibits hydrophilicity by treatment with an oxidizing gas. In addition, the substrate W may be a material whose main component is at least a part of Si. At this time, the substrate W in which at least a part of the substrate W is amorphous or crystalline Si is used. Can be used. In this case, the Si may be amorphous or crystalline P-doped (implanted) Si.

DESCRIPTION OF SYMBOLS 1 Substrate cleaning apparatus 2 Conveying part 3 Supply nozzle W Substrate S Surface to be cleaned

Claims (24)

A transport unit for transporting the substrate;
A supply nozzle for supplying a cleaning liquid having an oxidizing gas in a dissolved state and a microbubble state in a liquid capable of removing an oxide film on a surface to be cleaned transported by the transport unit;
With
The substrate cleaning apparatus, wherein the supply nozzle supplies the cleaning liquid at a flow velocity at which the microbubbles that have reached the surface to be cleaned move to the outer edge of the substrate while suppressing size change. A transport unit for transporting the substrate;
A plurality of supply nozzles for supplying a cleaning liquid having an oxidizing gas in a dissolved state and a microbubble state in a liquid capable of removing an oxide film on the surface to be cleaned of the substrate transported by the transport unit;
With
The plurality of supply nozzles are arranged side by side in a direction crossing the substrate transport direction along the surface to be cleaned of the substrate, and are arranged in a direction parallel to the surface to be cleaned in the substrate transport direction. An apparatus for cleaning a substrate, wherein the apparatus is inclined in the same direction, and is inclined in the same direction with respect to the surface to be cleaned of the substrate.   3. The substrate according to claim 2, wherein the plurality of supply nozzles respectively supply the cleaning liquid at a flow rate at which the microbubbles that have reached the surface to be cleaned move to the outer edge of the substrate while suppressing size change. Cleaning device. The substrate cleaning apparatus according to claim 1, wherein the oxidizing gas contains at least one gas of O ₂ and O ₃ . 4. The substrate cleaning apparatus according to claim 1, wherein the oxide film-removable liquid includes at least one liquid of HF, NH ₄ F, and H ₂ O ₂ .   4. The substrate cleaning apparatus according to claim 1, wherein the substrate is an insulating substrate or a single crystal Si substrate for forming a thin film transistor.   The substrate cleaning apparatus according to claim 6, wherein at least a part of the substrate exhibits hydrophobicity by processing the liquid from which the oxide film can be removed.   The substrate cleaning apparatus according to claim 6, wherein at least a part of the substrate exhibits hydrophilicity by treatment with the oxidizing gas.   9. The substrate cleaning apparatus according to claim 7, wherein at least a part of the substrate is a material mainly composed of Si.   The substrate cleaning apparatus according to claim 9, wherein at least a part of the substrate is amorphous or crystalline Si.   The substrate cleaning apparatus according to claim 10, wherein at least a part of the substrate is amorphous or crystalline P-doped Si. A transport unit that transports a substrate; and a supply nozzle that supplies a cleaning liquid having an oxidizing gas in a dissolved state and a microbubble state in a liquid capable of removing an oxide film on a surface to be cleaned of the substrate transported by the transport unit A substrate cleaning method for cleaning the substrate using a substrate cleaning apparatus comprising:
The supply liquid is supplied to the surface to be cleaned of the substrate transported by the transport unit by the supply nozzle at a flow velocity at which the microbubbles that have reached the surface to be cleaned move to the outer edge of the substrate while suppressing size change. And a substrate cleaning method. And a plurality of cleaning liquids each having an oxidizing gas in a dissolved state and a microbubble state in a liquid capable of removing an oxide film on a surface to be cleaned of the substrate transported by the transport unit, A substrate cleaning method for cleaning the substrate using a substrate cleaning apparatus comprising a supply nozzle,
The plurality of supply nozzles are arranged side by side in a direction crossing the substrate transport direction along the surface to be cleaned of the substrate, and are arranged in a direction parallel to the surface to be cleaned in the substrate transport direction. Are inclined in the same direction, respectively, and are inclined in the same direction with respect to the surface to be cleaned of the substrate,
The substrate cleaning method, wherein the cleaning liquid is supplied to the surface to be cleaned of the substrate transported by the transport unit by the plurality of supply nozzles.   The substrate cleaning according to claim 13, wherein the cleaning liquid is supplied at a flow rate by the plurality of supply nozzles so that the microbubbles that have reached the surface to be cleaned move to the outer edge of the substrate while suppressing size change. Method. The substrate cleaning method according to claim 12, wherein the oxidizing gas contains at least one gas of O ₂ and O ₃ . The oxide film removable liquid HF, claim 12, 13 or 14 substrate cleaning method according to, characterized in that it comprises at least one liquid NH ₄ F and _H 2 _{O 2.}   15. The substrate cleaning method according to claim 12, 13 or 14, wherein the substrate is an insulating substrate or a single crystal Si substrate for forming a thin film transistor.   The substrate cleaning method according to claim 17, wherein at least a part of the substrate exhibits hydrophobicity by processing the liquid from which the oxide film can be removed.   The substrate cleaning method according to claim 17, wherein at least a part of the substrate exhibits hydrophilicity by treatment with the oxidizing gas.   20. The substrate cleaning method according to claim 18, wherein at least a part of the substrate is made of a material mainly composed of Si.   21. The substrate cleaning method according to claim 20, wherein at least a part of the substrate is amorphous or crystalline Si.   The substrate cleaning method according to claim 21, wherein at least a part of the substrate is amorphous or crystalline P-doped Si. A display device manufacturing apparatus comprising a substrate cleaning device for cleaning a substrate used in a display device,
12. The display device manufacturing apparatus according to claim 1, wherein the substrate cleaning apparatus is the substrate cleaning apparatus according to any one of claims 1 to 11. A manufacturing method of a display device having a substrate cleaning process for cleaning a substrate used in the display device,
23. A method of manufacturing a display device, wherein, in the substrate cleaning step, the substrate is cleaned using the substrate cleaning method according to any one of claims 12 to 22.

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